1. Field of the Invention
The invention relates to a novel process for the production of a semiconductor or a semiconductor-containing layer which may be used in semiconductor-containing devices such as solar cells and particularly photoelectrochemical cells.
2. Description of Prior Art
U.S. Pat. No. 4,064,326 discloses a photoelectrochemical cell (PEC) device for directly converting radiant energy into electrical energy. FIG. 1 schematically illustrates a PEC having a photoelectrode 11, counterelectrode 13 and electrolyte 15, all contained within container 17. A load 19 is connected across the photoelectrode and counterelectrode. We have developed significant improvements of several components of such devices, e.g., the counterelectrode (see U.S. Patent Application Ser. No. 118,761, now abandoned), as well as improving cell construction and cell interconnections.
The photoelectrode is the key element of the phtoelectrochemical cell and is usually the most expensive part of the cell as it must often be monocrystalline. U.S. Pat. No. 4,064,326 discloses techniques for inexpensively preparing the photoelectrode, such as by electroplating, spraying, or sublimation.
Although such methods are satisfactory for certain semiconductor materials, other semiconductors do not lend themselves well to such methods of preparation and more expensive methods, such as sputtering or vacuum evaporation, may therefore become necessary.
Methods whereby a semiconductor paste is applied to a substrate and sintered, typified on the large scale by silk-screen printing, are well known for printing passive circuit components, in particular, the use of Cd(S,Se) and their mixtures as photoresistors. In 1967, Sihvonen et al. used printed CdS,Se for producing field effect transistors (PET's) and claimed that this was the first use of such a method for preparing other than passive components (J.Electrochem. Soc. 114, 96 (1967)).
Of greater interest is the use of silk-screened CdS for the preparation of solid state CdS-Cu.sub.2 S photovoltaic cells, described by Vojdani et al, (Electron Lett., 9, 128 (1973)). The results obtained were poor, due mainly to a high series resistance of the cells.
Until this time, no generally applicable, versatile method for the preparation of thin film photoelectrodes, which is both cheap and simple, has been described.